The present invention relates to an improvement of a tiled road surface suitable for use in an automobile test course or the like.
For constructing a low mu (xcexc) road surface for an automobile test course or the like there sometimes is used a precast concrete slab with tiles such as basalt tiles affixed to the surface thereof.
Basalt tile is fabricated by placing molten basalt into a mold and subsequent molding and surface roughening to a desired roughness. The basalt tile surface has a fine roughness and permits a stable formation of a thin water film thereon by sprinkling water thereto. A road surface having a thin water film formed thereon deteriorates the grip force of tire to a remarkable extent and therefore a road surface faced with basalt tiles is effective as a low xcexc road such as a test course or a snow-covered road experience course.
However, the basalt-tiled road surface is lost its fine surface roughness due to wear thereof caused by contact of a test tire therewith or due to years of exposure to the weather. Consequently, it becomes difficult to obtain a slip resistance value necessary for the test and it is no longer possible to achieve the object of the test. The required resistance value can be recovered by imparting a fine roughness again to the tile surface. Heretofore, the tile surface has been roughened using a grindstone. This conventional method, however, requires skill for the roughening work because the roughening must be done uniformly. Besides, a lot of time is needed for carrying out the work, thus giving rise to the problem that the test cannot be conducted over a long period of time.
In case of using basalt tiles in the form of a precast slab, various problems are encountered at present in the process of its fabrication and in the quality of the resulting product.
It is an object of the present invention to provide a method for recovering a slip resistance value of a basalt-tiled road surface to a desired value in a simple manner and in a short period, as well as an equipment suitable for used in the said method.
It is another object of the present invention to provide a basalt tile for affording such a low xcexc road precast slab as affords a uniform frictional resistance and can be fabricated easily.
It is a further object of the present invention to provide a precast slab for an automobile test course which precast slab is superior in working efficiency and can afford a road surface of a desired quality.